In the prior art, such screw connections are known, for example, from publication DE 20 2013 100 979 U1. A circular plug connector having a socket housing is disclosed therein. This connector has a locking means which is formed as a screw attachment and is arranged on the socket housing on the plug side. On the inside of the locking means there is provided an internal thread by means of which the circular plug connector can be screwed onto the mating plug connector in order to mechanically lock the plug connection.
In this construction, the rotatable holding of the screw attachment on the socket housing is conventionally achieved via a plurality of individual locking projections made of plastics material, which are formed on the inner surface of the screw attachment. Assembly of the plug connector housing, that is to say pushing of the screw attachment onto the socket housing, requires corresponding deformability of the socket housing and/or of the screw attachment.
A disadvantage of this prior art is that this rotatable fixing of the screw attachment to the socket housing is not sufficiently stable for many applications. For example, it has been shown in practice that problems arise in particular as a result of a heavy cable attached to the socket housing. Transverse forces caused thereby can at worst even separate the screw attachment from the socket housing as a result of a corresponding lever action, in particular under the action of vibration and regular and/or occasional shocks, and thereby interrupt the electrical connection. Corresponding situations can occur, for example, in the field of the foodstuffs industry, on production lines or also in railway applications, if the mating plug is mounted with an external mounting housing on a wall.
The German Patent and Trademark Office searched the following prior art in the priority application relating to the present application: DE 20 2012 101 303 U1, CH 232 218 A, DE 82 55 66 B and DE 20 2013 100 979 U1.